Energy conservation in String Theory

[Silviu]

Hello! I read some stuff about "attempts" to test some aspects of string theory at LHC and I was wondering if there is any deep reason behind the conservation of energy in general or it is just based on the fact that it holds in all the experiments (excluding uncertainty principle arguments). Like is there any theoretical reason why energy conservation should hold in multiple dimensions (and eventually at very high energies where stuff that we might not be able to predict can happen)?

 

[mfb]

The Noether theorem guarantees energy conservation in every system where the laws of the universe do not depend on the time.

While we cannot rule out (experimentally) that the fundamental constants of nature could show slight changes over time, no time-dependence has ever been measured.